The present invention relates, in general, to the treatment of materials in a controlled atmosphere, and more particularly, to surface treatment of materials in oxidizing or reducing atmospheres in the standing waves produced in the combustion zone of a helical flow furnace.
It is well known that various surface treatments can be utilized to enhance the characteristics of materials. For example, plastics can be treated by mechanical abrasion, solvents, acid etching, flame, corona, and hot or cold plasmas, to name a few. Such treatments may be utilized to clean or to activate the surface to receive a coating, to enhance bonding, and for a variety of other reasons as is well known. In the treatment of plastic materials through the use of plasmas, for example, extremely reactive process gases are brought into contact with an article in a reaction chamber, where the gases are ionized to create a plasma which reacts with the surface molecules to change the surface characteristics of the material. The selection of the process gas determines the nature of the surface modification, and the treatment of materials such as polymers can be carried out through the use of a wide variety of gases or gas mixtures, such as nitrogen, argon, oxygen, nitrous oxide, helium, water, ammonia, etc., with each producing a different surface modification in a reproducible and controllable way.